Method for extracting sulfur and inorganic salt from wet-desulfurization waste sulfur paste

Abstract

The invention discloses a method for extracting sulfur and inorganic salt from wet-desulfurization waste sulfur paste, which comprises the following steps: (1) mixing powdery sulfur paste and an organic solvent, stirring, filtering, washing the solid with the organic solvent, filtering to obtain a filtrate and a filter cake, merging the filtrates, decolorizing, carrying out vacuum distillation to remove the organic solvent and obtain a concentrated solution, cooling the concentrated solution, crystallizing, and filtering to obtain ammonium thiocyanate crystals and a mother solution; (2) drying the filter cake, mixing with water, stirring at room temperature for 0.5-2 hours, filtering, washing with water, merging the filtrates, and drying the filter cake to obtain a sulfur product; and (3) carrying out vacuum distillation on the filtrate, cooling to crystallize, and filtering to obtain the ammonium thiosulfate crystals. The method disclosed by the invention has the advantages of simple technique, short process, stable operation and strong adaptability to raw material yield and component fluctuation; and by treating the desulfurization waste liquid in the wet-desulfurization production process, the invention reutilizes the waste and reduces the environmental pollution. The extraction yield is high, and the purities of the extracted ammonium thiocyanate, sulfur and ammonium thiosulfate are high.

Description

technical field [0001] The invention relates to a method for extracting sulfur and inorganic salts from wet desulfurization waste sulfur paste. Background technique [0002] my country is the world's largest coal producer and consumer, SO emissions in the atmosphere 2 90% of that comes from dry coal. It is essential for desulfurization and decyanation treatment of coal-fired flue gas and gas. At present, my country's coking plants and other coal-fired tail gas treatment mostly use HPF wet desulfurization process. This method has the advantages of low investment, high desulfurization efficiency, low operating cost, low energy consumption, and easy operation. It is widely used in the field of desulfurization . [0003] However, in the wet desulfurization process, it will inevitably be produced in the desulfurization liquid phase (NH 4 ) 2 S 2 o 3 , NH 4 Inorganic salts such as CNS, most of these salts are accumulated in desulfurization waste liquid. When the salt conte...

AI Technical Summary

Problems solved by technology

For example, the Chinese patent application No. 2007101395747 uses catalytic oxidation to desalinate waste liquid containing salt, but a new pollution source is introduced during the treatment process, and the sewage still needs to be discharged

More patents, such as patents with application numbers 200710044751, 201010173380, and 200610031074, all utilize the difference in the solubility of ammonium thiosulfate and ammonium thiocyanate with temperature, and adopt a crystallization process to separate the salt in the waste liquid. There are problems such as long process, complicated operation and large equipment investment in the process

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